The invention is directed to a method of fabricating sputtering targets doped with non-metal additions including boron, carbon, nitrogen, oxygen and silicon by using atomized or crushed alloy powder or ultra fine boride, carbide, nitride, oxide, and silicide powder and hot isostatic pressing.
Cathodic sputtering processes are widely used for the deposition of thin films of material onto desired substrates. A typical sputtering system includes a plasma source for generating an electron or ion beam, a target that comprises a material to be atomized and a substrate onto which the sputtered material is deposited. The process involves bombarding the target material with an electron or ion beam at an angle that causes the target material to be sputtered or eroded. The sputtered target material is deposited as a thin film or layer on the substrate.
The target materials for sputtering process range from pure metals to ever more complicated alloys. The use of complex 3 to 6 element alloys is common in the sputtering industry. Alloying additions such as boron, carbon, nitrogen, oxygen, silicon and so on are frequently added to Cr-, Co-, Fe-based alloys and other intermetallic alloys to modify characteristics such as deposited film grain-size, surface energy and magnetic properties.
The presence of non-metal additions like boron, carbon, nitrogen, oxygen and silicon to target materials is either in the form of pure elements, e.g. boron and carbon, or in the form of compounds like nitride and oxide. The pure element phases such as boron and carbon and the compound phases like boride, carbide, nitride, oxide, and silicide, however cause spitting problems during sputtering. The present invention provides a solution to this problem.
The present invention relates to a novel method of fabricating sputtering targets that are doped with non-metals such as boron, carbon, nitrogen, oxygen and silicon or mixtures thereof or compounds of non-metals. The process comprises preparation of a pre-alloyed powder or selection of ultra fine compound powder of less than 10 microns, preferably less than 5 microns and most preferably less than 2 microns. It has been discovered that spitting will not occur when the above phases are in form of ultra fine particles of less than 10 microns in size. After the ultra fine powders are blended together, the powder blend is canned, followed by a hot isostatic press (HIP) consolidation. Powder processing as above is employed to make the target materials because of unique advantages over the prior art""s melting process, both technically and economically. These and other objectives of this invention will become apparent from the following detailed description.